I'm in the process of having a Sako rebarreled to 260 Remington. The rifle will have a regular 'factory' chamber not a tightneck chamber.

Unfortunately, Lapua does not offer brass in 260. However, I still want to use Lapua brass so my choice is to either neck up 243 brass or neck down 308 brass. I've necked WW Super 7x57 brass down to 6mm with a single pass in my RCBS 243 Winchester dies with no problems. Can either of the Lapua brass be properly resized with a simple pass in my RCBS 260 Rem dies?

It stands to reason that the neck downed 308 brass will result in a thicker neck than would the necked up 243 brass. Also, it would follow that IF I decided to neck turn the brass, it would be a better choice to turn the necked down 308 brass than the necked up 243 brass. But which would be the better choice of brass if I did not want to neck turn brass?

Is there any reason I should be concerned with a 'donut' forming due to necking the Lapua brass either up or down? More specifically, do I need concern myself with a 'donut' at all?

Bobby B.

I like to neck up. No neck turning or exotic case prep. And that is what I would do UNLESS you've a .243 in your gun collection. Then the possibility of putting a .260 in a .243 exist (I don't know that it would fit.)
One pass over your resizing button and Wa La, .260 brass. I did the same thing with some 1X .243 brass to a 7-08 and didn't lose a single case.
Only worry about the donuts that are hanging over your belt.

I've necked up 243, necked down 308 and 7/08 to make 260 brass.. all with a single pass and all experiencing ZERO problems..

the 308 might give you a little 'donut' around the neck.. but that doesn't present chambering problems in my 3 rifles in 260 Rem..

after the first shot that 'donut' disappears..

some one gave me some 308 Lapua brass, that had been shot about 30 times he said... I annealed it and necked it down to 7/08...

I've probably shot those cases a further 30 times...

I have no real need to buy brass with all the brass I have on hand.. but if I needed new brass, with proper care, and not redlining your loads.. that Lapua brass seems like it would last a lifetime...or enough to wear out a couple of barrels ..if nothing else..

I also neck up for my 260ai. I never had good results trying to neck down form 308.

Some people choose to neck down to achieve the thicker neck - better fit for a (loose) factory chamber.

- mike

I ordered 200 pieces of lapua 243 brass. My bullet of choice is the 130 Berger VLD. It'll be my MS and deer rifle.

Bobby B.